However, evidence of exophily by the major malaria vector A. gambiae in this study and by others in West Africa (Reddy et al., 2011; Tchouassi et al., 2012) raises the concern of the long term effectiveness of Indoor Residual Spraying (IRS) and Long lasting Insecticide-treated Nets (LLINs) in reducing outdoor transmission of malaria especially before bedtime and by people sleeping outdoors.
Outdoor transmission seems to be important only for temporary residents or visitors such as fishermen living in camping tents or provisory shacks.
Eradication was not attempted in areas where distances inhibited economic control or outdoor transmission predominated.
93, 94 Additional important options to prevent outdoor transmission in the context of integrated control include larviciding, as used in the ICEMR urban sites of Tumaco, Goa, Chennai, and Nadiad (Table 1), and environmental management.
In Africa, outdoor transmission is a growing concern since major changes are taking place in which parasite transmission is shifting from the dominant and highly endophilic vector, An. gambiae s.s., to the more exophilic and outdoor-adapted vector, An. arabiensis.
9, 10, 19, 20 Standard approaches such as indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are less likely to be as effective in some of these specific settings because of both human (mobility, housing structures, and low uptake of preventive measures) and mosquito behavior (early and outdoor transmission).
Evidently night shift workers will be at risk of outdoor malaria transmission.
It is important to better understand the risk factors associated with the outdoor air transmission of infections, but the best approach is not always straightforward.
Malaria control along the Vietnam Cambodia border presents a challenge for both countries' malaria elimination targets as the region is forested, inhabited by ethnic minority populations, and potentially characterized by early and outdoor malaria transmission.
A study in 2006 revealed that increasing outdoor dengue transmission, lower herd immunity and shift of vector control emphasis were some possible reasons for the upsurge of dengue (12).
